Silicious fire-brick and method of making the same.



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I To aZZ whom it may concern."

Be it known that I, HARRY A. KENNEDY, a citizen of the United States,residing at Clear-field, in the county-of Glearfield and State ofPennsylvania, have invented. certain new and useful Improvements inSilicious Fire.- Bricks and Methods of Making hit the Same,

of which the following is a specification,

Heretofore in the manufacture of refractory brick from silica rockandfire clay, the silica rock was crushed or gro ud to the desiredfineness, and this crus ed material was then mixed with fire cla or asuitable binder and molded into the blbcks or bricks, or the crushedsilica rock and fire clay were ground together and molded. T have foundthat such bricks will melt at a comparatively low temperature by reasonof the fact that the fine silica or sand which is molded into the brickalong with the coarser grade of material will readily flux or comblnewith the fire clay or other binder.

My invention, overcomes this dificulty and produces material of thischaracter which will stand a much higher heat than ordinary fire bricks,Without fiuning.

My invention, broadly stated, consists in using silica which is freefrom the finely pow ered silica or sand, and mining this coarser gradeof material with the fire clay or other binder whilev in its coarsecondition. @win to the absence of the finesa'nd. or powders material,the bricks or blocks thus formed will stand a onsiderably higher heatthan formerly,

in carrying out my invention, in its 're=, ierred form, the sihca rockis crushe or broken to a convenient size, such as egg size, or larger,and then delivered to a rolls crusher (any well known type) withsuficient maximum space between the rolls to further reduce theparticles to one-half to three-quarter inch size. 4 It is then furtherreduced in Y Specification of Letters Patent. application filedsepteniber as, 1917. serial no.

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Patented rear, as, rare, waste.

While the size of silica particles above named will uirements, yet thesesizes may be materially example, if the bricks are to be subjected toconsiderable friction'or abrasive action, smaller particles shouldlittle or no friction is put to them, and higher refractorincss wanted,they should be made coarser, L The fire claymay be repared by any of theusual methods, but% prefer to pass it through a wet chaser pen in whichit is round to the proper consistency for fire rick and then removed toa pug mill or mixing device wherein the coarser particles of silica areadded and the materials thoroughly mixed, ready for molding or applyingin the furnace. It is of the utmost importance that the properly sizedsilica should be mixed with the other materials or the binder in such away thatit is not pulverized or reduced to a smaller size, as even asmall amount of very fine silica or sand detracts from the refractoryquality of the brick The amount of the binder, whether composed ofplastic fire clay or any of the other bonds now used for refractorybrick, depends upon the conditions to which it is to be subjected, butwhere a highly refractory material is desired and the material is to besubjected to a small amount of friction, the amount of binder is reducedto as small an amount as possible, or may be dispensed with altogetherbyfiner grinding of-the fire clay as a mass, and thus making theconsistency such that it is a suilicient binder of itself; only enoughbinder in any'case being used to make the brick strong enough for thepurpose. intended, and to withstand handlin ,transportation, etc. Therepared is then molded into bricks and burnt.

The advantages of my invention result give best results for general re--from the facts which T have discovered, that by using only the coarserparticles of silica be used, and where ice and separating them from thefinely powdered particles or sand, the usual fiuuin action between fireclay particles of free silica when subjected to igh temperature does notoccur, and as the coarser silica particlesprevent the fire clay fromshrinking, by their own expansion under high temperature, the result isa con-- siderable higher reiractoriness, since the and finely dividesilica is added in a comparatively pure state and to ether with itsexpansion retains the air cel s of the entire mass for a longer periodof time. And further, since silica in this form improves therefractoriness, the question of expansion or contraction of the bricksmay be regulated completely by the amount and size of the granules ofsilica added, which for most purposes is of the utmost importance.

Many changes may be made in the method of obtaining the graded silicaparticles, as'

well as in the binder used, and the method of combining them, withoutdeparting from my invention.

I claim:

1. Silica brick composed of silica particles of substantial size asdescribed, free from the finely powdered silica or sand and mixed with abinder, substantially as described.

2. The method of making refractory brick containing free silica,consisting in reducing the sllica to the desired size, separating itfrom the finely powdered silica or sand, and then mixing 'with a binder,substantiallyas described.

3. The method of making silica brick consisting in reducing the silicato particles of the desired size, screening this material to gree offineness, screening the coarser parti- 1 cles from the finely powderedsilica or sand,

mixing these coarser particles with fire clay without pulverization orreduction to small size, and then molding and burning the brick,substantially as described.

5.v Silica brick com osed of particles of silica'of substantial slze, asdescribed, free from finely powdered silica, and mixed with a binder offire clay, substantially as described. V

In testimony whereof]: afiix my signature.

HARRY A. KENNEDY.

